1. Field of the Invention
This invention relatets to manually operated orifice type flow control valves generally used for controlling the rate of flow of liquid or gases in systems where input pressure is held constant, especially to the class of valves, where an interchangeable plug valve member that is rotatably switched from one position to another within the same flow path at corresponding surfaces, and having a plurality of round orifices therein, and is provided with mechanical means to precisely tune said flow rate through each orifice individually, to a desired setting value and to retain said adjustments for later use. The plug valve member is disposed in a cylindrical flat bottom bore of a ported valve body, having a positively sealed controlled flow passageway through the plug valve member to the outlet port, a passageway for uncontrolled return flow from the outlet port to the inlet port, and another passageway for safely relieving excess internal pressure through a relief port from therein.
Furthermore, in this invention interchangeable plug valve members having different internal configuration is employed to alter the functional character of the controlled flow passageway without impeding the intended functioning of the excess internal-pressure relief valve therein.
2. Description of the Prior Art
This invention relates to manually operated flow control valves and is particularly suited for, but not limited for applications to control the flow rate of liquids or gases, in laboratory apparatus and in chemical processing equipment as well as in machine tool operation and the like, that is utilized for specialized industrial applications in manufacturing of pharmaceutical as well as other chemical products, where conditions require that precisely adjusted flow rate is reliably maintained, quickly changed to, and to maintain another equally precise flow rate, completely block the controlled flow passageway, or to be switched back to the original setting without the need for re-calibrati on of previously established flow rate, while providing the means for relieving excess internal pressure from therein.
Heretofore, orifice type flow control valves of the prior art in which rotatable plug or disk valve member having a plurality of restrictive orifices therein, and one is being coaxially aligned in metal-to-metal contact with another opening as in U.S. Pat. No. 562,410 O. P. Moon, U.S. Pat. No. 1,017,292 J. Hyde, U.S. Pat. No. 1,621,876 L. H. Doerr, U.S. Pat. No. 2,897,936 R. R. Collins, U.S. Pat. No. 3,136,341 W. E. Walker, Sr., are shown without self-adjusting means to compensate for wear, while U.S. Pat. No. 934,932 M. P. Osbourn, U.S. Pat. No. 2,510,356 R. A. Werts, U.S. Pat. No. 2,685,891 A. L. Segelhorst, and U.S. Pat. No. 3,024,806 J. J. Colonna, are depending on compression spring for maintaining metal-to-metal contact for sealing action, and yet another U.S. Pat. No. 1,982,754 B. L. Peterson, provides for lubrication to minimize component wear, but problems of internal leakage have beset valves of this type to various degrees, where the restrictive orifice is not positively sealed therefore, precisely adjusted flow rate cannot be maintained reliably. In known devices of this kind, adjustment to a given size orifice opening cannot be made to attain a desired setting value, and for this reason there have been problems such as the difficulty of accomplishing highly accurate and positively controlled rate through the valve.